1. Field of the invention
The invention relates to a method of obtaining a one-piece module including an inductive winding. It also relates to one-piece electronic modules, and in particular to modules with a winding around a magnetic core, obtained by means of the method, for example converter modules.
2. Description of the Prior Art
Producing windings consisting of superposed turns consisting of conductive tracks carried by a printed circuit folded on itself to align the turns along an axis corresponding to the axis of the winding to be obtained is known in the art.
The document U.S. Pat. No. 5,801,611 describes an inductive device obtained in this way using a printed circuit on which winding turns are made on both faces at locations of the circuit which are stacked in parallel planes by multiple folding of the circuit on itself. It is necessary to provide connections passing through the printed circuit to connect the interior end of the spiral assembly made up of turns at a location on the printed circuit to a corresponding end of the spiral assembly according to the winding to be obtained. These connections are conventionally provided in the form of metal-plated holes which pass through the printed circuit to connect each of the two spiral assemblies. Solutions of this kind are relatively costly and relatively difficult to implement and their reliability is not always satisfactory.
The invention therefore proposes a method of obtaining a module including at least one inductive winding made up of one or more conductive tracks on a printed circuit film support on which the tracks form turns which are combined to form a winding or a plurality of parallel and/or coaxial windings, which method includes the following steps:
stacking a plurality of aligned modular printed circuit film elements carrying a set of turns which are intended to form part of a winding or of a plurality of parallel and/or coaxial windings and whose tracks terminate at or near the edge or one edge of the element that includes them,
molding an insulative material over the stacked assembly of modular elements to constitute a rigid block,
cutting the molded block laterally along the stack to expose the conductive tracks at a common alignment level and so that they are flush with the surface of one face of the block, which cutting step is performed at least once, and
creating connections on the face or faces of the block with which the modular conductive track elements are flush to interconnect them selectively and to connect them to connection means external to the module.
According to the invention, at least one end of a stack of modular elements is associated with one or more supplementary modular printed circuit elements which carry components and which have conductive frocks which terminate at a level corresponding to an alignment level of modular elements of the stack in order to perform the molding, cutting and connection creation steps simultaneously on all the associated modular elements.
In the context of the method according to the invention, an association of this kind enables a complete functional electronic module to be constructed by stacking modular elements and interconnecting all the modular elements by a connection operation common to all the elements.
According to the invention, at least one orifice is formed in the same position in the modular elements adapted to constitute a module to form therein a conduit enabling a core to be inserted through the modular elements.
This enables converter blocks including windings aligned along magnetic cores to be made in a minimum number of operations.
The invention also provides an electronic module in the form of a block which includes at least one inductive winding consisting of one or more conductive tracks on a printed circuit film support on which the tracks form turns which are combined to form the coil or parallel and/or coaxial coils, which module includes a stack of modular printed circuit film elements aligned at one edge at least and each carrying one or more turns which are to form part of a winding or of a plurality of parallel and/or coaxial windings and whose tracks terminate on a particular face at aligned edges of stacked modular elements at which conductive trocks are formed to connect turns to each other.
The resulting module has the advantage that it constitutes a rigid block, for example a cubical or rectangular parallelepipedal block, incorporating a connection network on at least one face.
In one variant of the invention the module is an electronic module incorporating a core and taking the form of a block which indudes at least one winding made up of conductive tracks on a printed circuit film support adapted to form turns, in a particular arrangement, and wherein at least some turns are combined to form a winding, which module indudes a stack of modular printed circuit film elements aligned at one edge at least and each carrying one or more turns which are to form part of a winding or a plurality of parallel and/or coaxial windings and whose tracks terminate at a face defined by aligned edges of stacked modular elements on which are formed conductive connecting tracks for connecting the turns to each other and to connection elements of external connection means, and at least some of the adjacent modules in the stack include identical openings at the center of at least one turn relating to a particular winding to form a passage for a core housed in a conduit formed by successive modules incorporating such openings.
In one variant of the invention, the module is a converter module, for example, and at least one supplementary modular printed circuit element carrying components is embedded in the molded block at one end at least of the stack of elements forming a winding or windings and each supplementary element includes conductive tracks terminating at and electrically connected to conductive tracks formed on a particular face of the block by aligned edges of stacked modular elements.
The invention, its features and its advantages are explained in the following description, which is given with reference to the accompany drawing.